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For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2000 🢒 Impala 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 DTC P1585 Cruise Control Inhibit Output Circuit

Object Number: 515405 Size: SF
Engine Controls Component Views
Engine Data Sensors-MAF, EVAP Vent, EVAP Purge, EGR
Handling ESD Sensitive Parts Notice
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

Circuit Description

Output driver modules (ODMs) are used by the PCM to turn on many of the current-driven devices that are needed to control various engine and transaxle functions. Each ODM is capable of controlling up to 7 separate outputs by applying ground to the device which the PCM is commanding ON. Unlike the quad driver modules (QDMs) used in prior model years, ODMs have the capability of diagnosing each output circuit individually. If an improper voltage level has been detected on the output circuit which controls the stepper motor cruise control inhibit circuit, DTC P1585 will set

Conditions for Setting the DTC
    • The ignition is ON.
    • An improper voltage level has been detected on the output circuit which controls the cruise control inhibit.
    • The above conditions are present for at least 30 seconds.

Action Taken When the DTC Sets

The PCM stores conditions which were present when the DTC set as Failure Records only. This information will not be stored as Freeze Frame Records.

Conditions for Clearing the MIL/DTC
    • The DTC becomes history when the conditions for setting the DTC are no longer present.
    • The history DTC clears after 40 malfunction free warm-up cycles.
    • The PCM receives a clear code command from the scan tool.

Diagnostic Aids

Check for the following conditions:

    • Poor connection at the PCM -- Inspect harness connectors for the following conditions:
       - Backed out terminals
       -  Improper mating
       -  Broken locks
       - Improperly formed or damaged terminals
       -  Poor terminal to wire connection
    • Damaged harness -- Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the PCM, turn ON the ignition and observe a Digital Multimeter connected between the cruise control inhibit control circuit and ground at the PCM harness connector while moving connectors and wiring harnesses related to the stepper motor cruise control module. A change in voltage will indicate the location of the malfunction.

If the DTC cannot be duplicated and is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set. Also refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. Normally, ignition feed voltage should be present on the inhibit control circuit with the PCM disconnected and the ignition turned ON .

    2.

  2. Checks for a shorted component or a short to B+ on the inhibit control circuit. Either condition would result in a measured current of over 500 milliamps. Also checks for a component that is going open while being operated, resulting in a measured current of 0 milliamps.

    3.

  3. Checks for a short to voltage on the inhibit control circuit.

    4.

  4. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.

DTC P1585 -- Cruise Control Inhibit Control Circuit

Step

Action

Values

Yes

No

1

Did you perform the Powertrain On-Board Diagnostic (OBD) System?

--

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

2

  1. Turn OFF the ignition.
  2. Disconnect the PCM.
  3. Turn ON the ignition, with the engine OFF .
  4. Using a DMM measure voltage between the inhibit control circuit at the PCM harness connector and ground.

Does the voltage measure near the specified value?

B+

Go to Step 3

Go to Step 6

3

  1. Connect the DMM to measure current between the cruise inhibit control circuit at the PCM harness connector and ground.
  2. Monitor the current reading for at least 2 minutes.

Does the current reading remain between the specified values?

0.001-0.5 amp

(1-500 mA)

Go to Step 11

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Disconnect the cruise control module (leave the PCM disconnected).
  3. Turn ON the ignition, with the engine OFF.
  4. Using the Digital Multimeter measure voltage between the cruise inhibit control circuit and ground.

Does the voltage measure the specified value?

0 V

Go to Step 10

Go to Step 5

5

Locate and repair short to voltage in the cruise inhibit control circuit. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

--

6
  1. Turn OFF the ignition.
  2. Test the feed fuse for the cruise control module. Refer to Power and Grounding Component Views in Wiring Systems.

Is the fuse open?

--

Go to Step 7

Go to Step 8

7
  1. Locate and repair short to ground in ignition feed circuit for the cruise control module. Refer to Wiring Repairs in Wiring Systems.
  2. Replace the fuse.

Did you find and correct the condition?

--

Go to Step 16

--

8
  1. Disconnect the cruise control module.
  2. Turn ON the ignition, with the engine OFF.
  3. Measure voltage between the ignition feed circuit for the cruise control module and ground.

Does the voltage measure near the specified value?

B+

Go to Step 9

Go to Step 13

9
  1. Test the cruise inhibit control circuit for an open or a short to ground.
  2. If a problem is found, repair as necessary. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 10

10
  1. Inspect for the following conditions:
    2. • The cruise inhibit control circuit for a poor connection at the PCM.
    • The cruise inhibit control circuit for a poor connection at cruise control module.
    • The cruise control module ignition feed circuit for a poor connection at the cruise control module.
  2. If a problem is found, repair as necessary. Refer to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 14

11
  1. Turn OFF the ignition.
  2. Reconnect the PCM.
  3. Disconnect the cruise control module.
  4. Turn ON the ignition, with the engine OFF.
  5. Connect a test lamp between the cruise inhibit control circuit and the ignition feed circuit at the cruise control module harness connector.
  6. Using a scan tool outputs test function, cycle the cruise inhibit output ON and OFF.

Does the test lamp flash ON and OFF?

--

Go to Diagnostic Aids

Go to Step 12

12
  1. Inspect the cruise inhibit control circuit for a poor connection at the PCM.
  2. If a problem is found, repair as necessary. Refer to Connector Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 15

13

Locate and repair open in ignition feed circuit to the cruise control module. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

--

14

Replace the cruise control module.

Did you complete the replacement?

--

Go to Step 16

--

15

Important:: The replacement PCM must be programmed.

Replace the PCM. Refer to Powertrain Control Module Replacement/Programming .

Did you complete the replacement?

--

Go to Step 16

--

16
  1. Use a scan tool to Clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK